Analytical and numerical assessments of local overpressure from hydrogen gas explosions in petrochemical plants

Accurate prediction of pressure rise is important for safety assessments of a petrochemical plant in the event of an explosion accident. The sudden pressures arising from gas explosions at various hydrogen concentrations in air have been predicted analytically and numerically. These solutions were compared against experimental data. The analytical solution, based on the self‐similar solution for pointwise strong explosions in an open space, which assumed no energy loss and premixed fuel‐air mixture, reasonably predicted the explosive‐ignition detonation case while the numerical solutions were more suitable to model spark‐ignition deflagration cases that accounted for the effect of turbulence arising from three‐dimensionality and presence of obstacles in the computational domain. Comparison of both analytical and numerical results against experimental data indicates that their differences are within a 30% margin. The analytical model presented herein can be useful for field engineers who want conservative estimates of the overpressure resulting from explosive‐ignition detonation. Copyright © 2016 John Wiley & Sons, Ltd.     

Saliency detection based on seed propagation in a multilayer graph

Multimedia Tools and Applications - This paper presents a saliency detection algorithm based on the seed propagation in graph representation of image. First, the image is divided into...     

Anti-inflammatory and anti-genotoxic activity of branched chain amino acids (BCAA) in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophages

Food Science and Biotechnology - The purpose of this study was to evaluate the anti-inflammatory and anti-genotoxic activity of branched-chain amino acids (BCAAs) in lipopolysaccharide (LPS)...     

Analysis of ethanol in soy sauce using electronic nose for halal food certification

The purpose of this study was to analyze ethanol content in soy sauce using mass spectrometry (MS) with electronic nose (e-nose) to determine if MS e-nose can replace gas chromatographic analysis for halal certification. Gas chromatography–flame ionization detector (GC-FID), the standard method of ethanol content, was used to analyze 24 different kinds of soy sauce. Ethanol was detected from 13 soy sauce samples in the concentration range of 0.0004–1.7wt%. The MS e-nose data were analyzed by discriminant function analysis (DFA). Based on an addition method, the results were more than 96.6% accurate when the ethanol concentrations were greater than 0.5%. A high correlation between the first score of the DFA plot and the ethanol concentration was observed. Thus, mass spectrometry based on e-nose is an efficient method for determining ethanol as a primary screening tool for halal certification.     

Determination of total arsenic content and arsenic speciation in different types of rice

Food Science and Biotechnology - The objectives of this study was to examine the amount of total arsenic and arsenic speciation in different types of rice from two areas in Korea using inductively...     

Policy measures to overcome barriers to energy renovation of existing buildings

Even though there is great potential to reduce greenhouse gas emissions from existing buildings, most political effort in Korea has been focused on the construction of new buildings; few concrete measures have been taken to limit greenhouse gas emissions from existing buildings. This study examined the potential to reduce greenhouse gas emissions from existing residential buildings as a means to cope with global warming. Additionally, several barriers to improving the energy performance of existing dwellings instead of constructing new dwellings were explored. The major barriers to improving the energy performance of existing residential buildings are: (1) a lack of awareness; (2) financial reasons; (3) insufficient information; and (4) the absence of regulatory systems. To overcome such barriers, systems adopted and implemented in developed European countries were considered and their feasibility was verified so that political measures could be suggested to improve the energy performance of existing dwellings in Korea.     

Numerical analysis of flow distribution for combined weapon system in environmental tester

Thermal behaviors of combined weapon systems were analyzed by developed computational programs in this study. Also, temperature distributions of the materials of the system were measured according to the experimental conditions. Field tests that reflected the calculated thermal flow characteristics and the measured temperature distributions of the materials were prepared in a large environmental tester for the weapon systems. Boundary conditions of the analysis were the inlet and outlet conditions of the environmental tester and the low temperature limit of ?32°C. The soaking time of the system, including a fuel tank and a battery in the environmental tester, was obtained by the programs developed in this study to carry out the experiment in the predicted conditions.     

Robotics‐based telepresence using multi‐modal interaction for individuals with visual impairments

Although many assistive devices have been developed and utilized to aid in daily living, the most general assistive means for individuals with visual impairments are the walking cane and guide dogs. These assistive means are effective in assisting the user in navigating within an environment; however, the navigation space is limited to the proximal environment of the user. Thus, in this paper, we discuss a method to increase the range of accessibility to a remote environment through robotic embodiment that enables teleoperation and teleperception through multi‐modal feedback. In order to transform remote spatial information into a non‐visual modality, we present a framework for utilizing an RGB‐D‐based depth camera, a mobile robot, and a haptic interface for 3D haptic rendering to accomplish the goal of haptic exploration of a remote environment. Experiments with three different control methods for robot interaction are designed for users with and without visual impairments. Several hypothesis are built to study the correlation between control/feedback modality and performance in telerobotic operations. Results show that users performed best when combining semi‐autonomous navigation with 3D haptic exploration and also rated their experience with our system as fairly good. Copyright © 2014 John Wiley & Sons, Ltd.     

Interference-free tool path generation in five-axis machining of a marine propeller

The manufacture of a marine propeller typically requires long lead-time to generate five-axis tool paths. It usually takes several days to generate satisfactory tool paths with a general purpose CAD/CAM system. This paper proposes a novel methodology that generates effective five-axis tool paths for marine propellers. The machining of a propeller is accomplished in three steps: rough cut, semi-finish cut, and finish cut. For generating accurate finish cut tool paths, the proposed system computes check vectors that determine a maximum range of valid tool motion based upon tool size and passage width for each CL (Cutter Location) point along the tool path. Interference-free tool paths can be acquired by positioning the tool inside the two check vectors. The modelling capability for propellers is also of importance because it determines the eventual success or failure of the whole process. An iterative B-spline surface modelling technique is employed to improve the accuracy of the models and to increase the productivity. The proposed system generates interference-free tool paths with superior surface finish and reduces lead-time to manufacture a propeller. The system validation and sample results are given and discussed.     

Role of spheroidized carbides on the fatigue life of bearing steel

The fatigue characteristics of bearing steel in ultrasonic fatigue tests are investigated with regard to the role of spheroidized carbides. The results show that, despite a similar hardness level, the bearing steel with spheroidized carbide has a much longer fatigue life than steel without, and that the failure mechanism differs in each case. All the samples of SAQT-processed steel examined using ultrasonic fatigue tests were characterized by a conventional fish-eye structure, which implies they went through subsurface-originated or interior inclusion-induced failure. On the contrary, it was shown that surface-induced failure prevailed in the QT-processed steel without spheroidized carbide. The results suggest spheroidized carbide may strengthen the tempered martensitic matrix of the bearing steel and concentrate the stress around an inclusion rather than at the surface, allowing for prolonged fatigue life over the steel without spheroidized carbide.